It is an important matter to develop a technique for improving image quality in the field of silver halide color photographic materials. Methods for obtaining high image quality with small formats have been developed one after another in recent years. However, it is believed that these methods still have problems. Moreover, it has been demanded to further improve these methods.
DIR compounds are conventionally used at present to improve sharpness, particularly edge effect. The DIR compounds which are conventionally used are DIR couplers which release imagewise a development inhibitor by the coupling reaction with the oxidation product of a color developing agent to form a developed dye.
However, when the DIR couplers are used, there is a problem that when the dye formed by the coupling reaction is different from a dye obtained by a main coupler, color turbidity is formed and this phenomenon is not preferred from the viewpoint of color reproducibility. To prevent this color turbidity from being formed, DIR couplers having a hue equal to the developed dye of each of the main yellow, magenta and cyan couplers must be developed, and DIR couplers of as many as three types of couplers must be developed, said DIR couplers having the optimum reactivity. Costs in the development and synthesis of these DIR couplers are increased. Thus, non-color forming DIR compounds have been demanded.
The non-color forming DIR compounds can be classified into two groups, that is, a coupling type and an oxidation-reduction type according to the reaction system with the oxidation products of color developing agents. The coupling type compounds include compounds described in JP-B-51-16141 (the term "JP-B" as used herein means an "examined Japanese patent publication"), JP-B-51-16142 and U.S. Pat. Nos. 4,226,943 and 4,171,223. The oxidation reduction type compounds include the DIR hydroquinone compounds described in U.S. Pat. Nos. 3,379,529 and 3,639,417, JP-A-49-129536 (the term "JP-A" as used herein means an "unexamined published Japanese patent application"), JP-A-64-546 and JP-A-2-21127 and DIR hydrazine compounds described in JP-A-61-213847, JP-A-64-88451 and U.S. Pat. No. 4,684,604. It is preferred that a development inhibitor is released from the DIR compound in the first development stage when reversal color light-sensitive materials are processed in the processing stage including B/W development (first development) and color development (second development). This is because in the second development stage, it is intended to rapidly develop all of the silver halides which are not developed in the first development stage and hence the silver development rate is very quick. Accordingly, when a development inhibiting action is imagewise effected in the second development stage, silver development is retarded and processing in the color development becomes unstable. Hence, it is preferred that the DIR compounds are reacted in the first development stage. In this case, however, the oxidation-reduction type DIR compounds capable of reacting with the oxidation product of developing agents for B/W must be used.
When conventional yellow couplers are used in combination with the oxidation-reduction type DIR compounds, there are problems because improving the edge effect can scarcely be obtained and the performance of the light-sensitive materials is liable to be changed during storage under moist heat conditions.